Error when saving cache file for very long URL: ENAMETOOLONG (File name too long)

[marcel-rf]

I am trying to download non-public images from amazon's s3.
To do this I have to generate a pre-signed url that includes a bunch of long parameters like the signature, and the library crashes because it wants to write a file whose name lenght exceeds the allowed limit.

I am now trying to hack the cache to use shorter version of the url as filename, but I think that would probably mess up the entire cache system for s3 pictures.